- Failure to thrive in infancy (HP:0001531). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:284417)
- Hyperglycinemia (HP:0002154): An elevated concentration of glycine in the blood. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:284417)
- Feeding difficulties in infancy (HP:0008872): Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:284417)
- Primary microcephaly (HP:0011451): Head circumference below 2 standard deviations below the mean for age and gender at birth. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:284417)
- Hyposerinemia (HP:0012279): Reduced concentration of serine in the blood. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:284417)
- Profound global developmental delay (HP:0012736): A profound delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:284417)
- Inappropriate crying (HP:0030215): Uncontrolled episodes of crying occur without any apparent motivating stimuli. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:284417)
- Thickened nuchal skin fold (HP:0000474): A thickening of the skin thickness in the posterior aspect of the fetal neck. A nuchal fold (NF) measurement is obtained in a transverse section of the fetal head at the level of the cavum septum pellucidum and thalami, angled posteriorly to include the cerebellum. The measurement is taken from the outer edge of the occiput bone to the outer skin limit directly in the midline. An NF measurement greater than 5 mm at 14 to 17+6 weeks of gestation, or 6 mm at 18 to 28 weeks has been associated with a markedly increased risk for Down syndrome. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Seizure (HP:0001250): A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Hypertonia (HP:0001276): A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Intrauterine growth retardation (HP:0001511): An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Cerebral white matter hypoplasia (HP:0012430): Underdevelopment of the cerebral white matter. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:284417)
- Hypertelorism (HP:0000316): Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Sloping forehead (HP:0000340): Inclination of the anterior surface of the forehead from the vertical more than two standard deviations above the mean (objective); or apparently excessive posterior sloping of the forehead in a lateral view. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Short neck (HP:0000470): Diminished length of the neck. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Spastic tetraparesis (HP:0001285): Spastic weakness affecting all four limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Cerebellar vermis hypoplasia (HP:0001320): Underdevelopment of the vermis of cerebellum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Lissencephaly (HP:0001339): A spectrum of malformations of cortical development caused by insufficient neuronal migration that subsumes the terms agyria, pachygyria and subcortical band heterotopia. See also neuropathological definitions for 2-, 3-, and 4-layered lissencephaly. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Craniosynostosis (HP:0001363): Craniosynostosis refers to the premature closure of the cranial sutures. Primary craniosynostosis refers to the closure of one or more sutures due to abnormalities in skull development, and secondary craniosynostosis results from failure of brain growth. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Bilateral talipes equinovarus (HP:0001776): Bilateral clubfoot deformity. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- EEG with polyspike wave complexes (HP:0002392): The presence of complexes of repetitive spikes and waves in EEG. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Limb joint contracture (HP:0003121): A contracture (chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin) that prevent normal movement of one or more joints of the limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Depressed nasal bridge (HP:0005280): Posterior positioning of the nasal root in relation to the overall facial profile for age. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Knee flexion contracture (HP:0006380): A type of knee joint contracture in which the knee is in a fixed bent (flexed) configuration such that it cannot be straightened actively or passively. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Ankle flexion contracture (HP:0006466). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Lateral ventricle dilatation (HP:0006956). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Paroxysmal involuntary eye movements (HP:0007704): Sudden-onset episode of abnormal, involuntary eye movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Ichthyosis (HP:0008064): An abnormality of the skin characterized the presence of excessive amounts of dry surface scales on the skin resulting from an abnormality of keratinization. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Simplified gyral pattern (HP:0009879): An abnormality of the cerebral cortex with fewer gyri but with normal cortical thickness. This pattern is usually often associated with congenital microcephaly. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Epileptic spasm (HP:0011097): A sudden flexion, extension, or mixed extension-flexion of predominantly proximal and truncal muscles that is usually more sustained than a myoclonic movement but not as sustained as a tonic seizure. Limited forms may occur: Grimacing, head nodding, or subtle eye movements. Epileptic spasms frequently occur in clusters. Infantile spasms are the best known form, but spasms can occur at all ages. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- EEG with focal sharp waves (HP:0011196): EEG with focal sharp transient waves of a duration between 80 and 200 msec. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Gastrostomy tube feeding in infancy (HP:0011471): Feeding problem necessitating gastrostomy tube feeding. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Delayed myelination (HP:0012448): Delayed myelination. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Nasogastric tube feeding (HP:0040288): The condition of inability to eat normally treated by placement of a thin tube through the nose into the stomach that is then used to carry food. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
- Cyanotic episode (HP:0200048). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:284417)
These phenotypes are associated with the disease Phosphoserine aminotransferase deficiency, infantile/juvenile form (ORPHA:284417).